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mapping

  Asked By: Jody    Date: Jun 25    Category: Java    Views: 668
  

could anybody help about n to n mapping in hibernate please(between
2 tables and the 3th one which is the relation between them) .
I tried to read from the 3th table then to complete the query but it
returns empty.


<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 2.0//EN"
"hibernate.sourceforge.net/...rnate-mapping-2.0.dtd">

<hibernate-mapping>

<class name="eg.Relation" table="tblRelation" >

<composite-id>

<key-many-to-one name="codeformTable1" class="eg.Table1"
column="codeformTable1"/>
<key-many-to-one name="codeformTable2" class="eg.Table2"
column="codeformTable2"/>

</composite-id>


<property name="fieldTable3" column="fieldTable3"
type="java.lang.Integer" />

</class>
</hibernate-mapping>

package general;

import java.util.List;

import net.sf.hibernate.HibernateException;
import net.sf.hibernate.ObjectNotFoundException;
import net.sf.hibernate.Query;
import net.sf.hibernate.Session;

import net.sf.hibernate.Hibernate;



public class CService
{

private static CService instance = null;

private CService()
{

}


public static synchronized CService getInstance()
{

if (instance == null)
{
instance = new CService();
}
return instance;
}



public List getCList(String s)
{


Session session = ConnectionFactory.getInstance
().getSession();

try
{

Query query =session.createQuery("select c
from eg.Relation c ");
if((query.list()).isEmpty() )
System.out.println("empty");
return query.list();

}
catch (HibernateException e)
{
System.err.println("Hibernate Exception" +
e.getMessage());
throw new RuntimeException(e);
}
finally
{
if (session != null)
{
try
{
session.close();
}
catch (HibernateException e)
{
System.err.println
("Hibernate Exception" + e.getMessage());
throw new RuntimeException
(e);
}

}
}
}


}

.jsp
<%
List cList = CService.getInstance().getCList(s);
request.setAttribute("cList", cList);
if (cList.isEmpty())
System.out.println("empty_2");
%>

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